Acyclic Jacobi Diagrams

We propose a simple new combinatorial model to study spaces of acyclic Jacobi diagrams, in which they are identified with algebras of words modulo operations. This provides a starting point for a word-problem type combinatorial investigation of such spaces, and provides fresh insights on known results.Comment: 18 pages, 7 figures. Refernces added. Section 2 rewritten. Proof of Theorem 1.1 rewritten. To appear in Kobe J. Mat

Dual-Context Calculi for Modal Logic

We present natural deduction systems and associated modal lambda calculi for the necessity fragments of the normal modal logics K, T, K4, GL and S4. These systems are in the dual-context style: they feature two distinct zones of assumptions, one of which can be thought as modal, and the other as intuitionistic. We show that these calculi have their roots in in sequent calculi. We then investigate their metatheory, equip them with a confluent and strongly normalizing notion of reduction, and show that they coincide with the usual Hilbert systems up to provability. Finally, we investigate a categorical semantics which interprets the modality as a product-preserving functor.Comment: Full version of article previously presented at LICS 2017 (see arXiv:1602.04860v4 or doi: 10.1109/LICS.2017.8005089

On the Logic of Evolution and the Vanity of Scientism

The cultural debate about Creationism contra evolution by natural selection may be far from over, but the logic underlying it is settled. Creationism is ill-suited to take the place of methodological naturalism for the investigation of biology. In this paper, I survey how philosopher Elliott Sober uses some well-formed concepts from statistics and epistemology, including the nature of evidence, data, as well as the contemporary theory of evolution by natural selection to destroy Creationism as a viable theory once and for all. Creationism is a demonstrable logical fallacy, one that has no support biblically, or in science, but is a thoroughly political conception. I also challenge the idea that disproving Creationism means that the nature of ultimate reality is described by ontological physicalism. I argue contemporary empiricists are mistaken about the significance of the logical defeat of the erroneous system of Creationism, and that the ontological statements about unknowable facets of existence made by materialists about reality are not obviously the case. Due to the indispensability of numbers in instantiating empirical theories, I argue that numbers are quasi-Platonic abstract entities that transcend space-time. I argue that the elements of numbers are not invented, but discovered by the human mind, and are not reducible to psychological factors

Holding Space for Voices that Do Not Speak: Design Reform of Rating Systems for Platforms in GREAT Economies

Researchers can examine ethical implications of online rating systems to understand how they function as ‘knowledge instruments’ and affect social relations and networks connected with them. Research should address the fact that the underlying economic structures that design and deploy knowledge producing ‘technical objects’ on online platforms are not egalitarian and may create new circles of exclusion. Exploring implications of this for a starkly unequal country like India, we illustrate our ideas by integrating induction and abduction to study rating systems on a pan-India food discovery and delivery platform. Rating systems are borrowed from WEIRD contexts and our findings imply that the instrument studied here is designed to hear only some of many voices. Consequently, they might be ‘institutionalizing’ knowledge that is problematic for GREAT domains in which they are imposed. We highlight the need for decolonization of research approaches for GREAT domains and critical research of technical knowledge objects

Herbal highs: review on psychoactive effects and neuropharmacology

Background: A new trend among users of new psychoactive substances’ the consumption of “herbal highs”: plant parts containing psychoactive substances. Most of the substances extracted from herbs, in old centuries were at the centre of religious ceremonies of ancient civilizations. Currently, these herbal products are mainly sold by internet web sites and easily obtained since some of them have no legal restriction. Objective: We reviewed psychoactive effects and neuropharmacology of the most used “herbal highs” with characterized active principles, with studies reporting mechanisms of action, pharmacological and subjective effects, eventual secondary effects including intoxications and/or fatalities Method: The PubMed database was searched using the following key.words: herbal highs, Argyreia nervosa, Ipomoea violacea and Rivea corymbosa; Catha edulis; Datura stramonium; Piper methysticum; Mitragyna speciosa. Results: Psychoactive plants here reviewed have been known and used from ancient times, even if for some of them limited information still exist regarding subjective and neuropharmacological effects and consequent eventual toxicity when plants are used alone or in combination with “classical” drugs of abuse. Conclusion: Some “herbal highs” should be classified as harmful drugs since chronic administration has been linked with addiction and cognitive impairment; for some others taking into consideration only the recent trends of abuse, studies investigating these aspects are lacking

Changes in the transcriptome and metabolome during the initiation of growth cessation in hybrid aspens

At 9 550 years of age, Old Rasmus, a Norway spruce (Picea abies), located in the Dalarna province in Sweden is recognized as the oldest surviving tree in the world. Old Rasmus exemplifies a robust capacity to survive in changing conditions, making trees a unique and fascinating subject for study. For perennial trees located in high latitudes one of the most important survival mechanisms is to be able to predict the coming winter and to halt growth in time. Poplars (Populus sp.) use mainly two environmental signals, temperature and light (day length), to predict the coming winter. However, of these two signals day length predominates. Towards the end of summer when the days shorten the trees recognize a critical day length and thereafter start the processes to halt growth and prepare for the impending winter. This thesis focuses on the early gene expression and metabolic responses exhibited in hybrid aspen (Populus tremula L. x tremuloides) induced by a shorter day length below the critical day length. In our effort to identify and describe these responses we used high throughput technologies such as microarray and GC-MS to generate data. We show that similar responses exists in hybrid aspen as in Arabidopsis, with initial responses in carbohydrate and secondary metabolism pathways and circadian clock associated genes. Our results provide evidence that the hormone Gibberellin (GA) is linked with the photoperiodic regulation pathway by affecting PHYTOCHROME A (PHYA) expression and thereby the levels of transcripts that act downstream of PHYA. We also suggest that in Populus the protein GIGANTEA1 (GI1) might be able to influencing growth cessation process by regulating the expression of FLOWERING LOCUS T2 (FT2) independently of CONSTANS2 (CO2)

Presence of Inulin-Type Fructo-Oligosaccharides and Shift from Raffinose Family Oligosaccharide to Fructan Metabolism in Leaves of Boxtree (Buxus sempervirens)

from raffinose family oligosaccharide to fructan metabolism in leaves of boxtree (Buxus sempervirens) Wim Van den Ende1,* Marlies Coopman1, Rudy Vergauwen1, André Van Laere11 KU Leuven, Laboratory of Molecular Plant Biology, Institute of Botany and Microbiology, Kasteelpark Arenberg 31, B-3001 Leuven, Belgium* Correspondence: Wim Van den Ende, Laboratory of Molecular Plant Biology,Institute of Botany and Microbiology, Kasteelpark Arenberg 31, B-3001 Leuven, Belgium tel +32 16321952; fax +32 16321967;[email protected]: inulin, oligosaccharides, stress, RFO, fructanAbstractFructans are known to occur in 15% of flowering plants and their accumulation is often associated with stress responses. Typically, particular fructan types occur within particular plant families. The family of the Buxaceae, harbouring Pachysandra terminalis, an accumulator of graminan- and levan-type fructans, also harbours boxtree (Buxus sempervirens), a cold and drought tolerant species. Surprisingly, boxtree leaves do not accumulate the expected graminan- and levan-type fructans but small inulin fructo-oligosaccharides (FOS: 1-kestotriose and nystose) and raffinose family oligosaccharides (RFO: raffinose and stachyose) instead. The seasonal variation in concentrations of glucose, fructose, sucrose, FOS and RFO were followed. Raffinose and stachyose peaked during the winter months, while FOS peaked at a very narrow time-interval in spring, immediately preceded by a prominent sucrose accumulation. Sucrose may function as a reserve carbohydrate in winter and early spring leaves. The switch from RFO to fructan metabolism in spring strongly suggests that fructan and RFO fulfil distinct roles in boxtree leaves. RFO may play a key role in the cold acclimation of winter leaves while temporal fructan biosynthesis in spring might increase sink strength to sustain the formation of new shoots